New rotavirus vaccines reduce illness burden in northeast Florida

Babies in northeast Florida are healthier today thanks to two new vaccines against rotavirus, the most common cause of severe diarrhea in children younger than 5.

The number and severity of rotavirus infections decreased greatly after the vaccines were introduced in the United States in 2006 and 2008, respectively. Reduced rotavirus infections mean better health and quality of life for children, greater peace of mind for parents and caregivers, and cost savings for hospitals and health-care providers.

The findings appear this month in The Pediatric Infectious Disease Journal.

“Once those thousands of vaccines were distributed, the disease incidence decreased and hospitalization decreased,” said principal investigator Mobeen Rathore, M.D., a professor and chief of pediatric infectious diseases and immunology at the University of Florida College of Medicine-Jacksonville and Wolfson Children’s Hospital. “This is now considered the standard of care, and parents should be asking their pediatricians for the vaccine.”

The Centers for Disease Control and Prevention, the American Academy of Pediatrics and the World Health Organization recommend that the rotavirus vaccine, which is delivered orally, be given to children between 6 and 24 weeks old. The organizations have sought to allay recent concerns about the vaccines by citing its proven safety in large clinical trials.

Rotavirus infection is most common in children younger than 2 years old, and most severe in children younger than 1 year. Tens of thousands of children in the United States are affected each year, and many have to be hospitalized. Before 2006 when the first vaccine became available, rotavirus infection resulted in the hospitalization of up to 70,000 children, the deaths of up to 60, and hundreds of thousands of emergency department and outpatient visits each year, according to the CDC. More than a half-million children worldwide die from the disease every year.

Using hospitalization as a marker for the severity of illness, the UF researchers reviewed six years’ worth of Wolfson Children’s Hospital records for patients younger than 18 in the period before and after the vaccines were introduced. The hospital is the only tertiary care center serving children in northeast Florida.

In the period from 2004-06, before the vaccines were available, almost one-third of children tested were positive for the virus. Afterward, from 2007-09, the fraction of positive tests dropped to just over one-tenth. Post-vaccine era rotavirus infection also accounted for a much smaller proportion of hospitalizations — 20 percent, compared with more than 70 percent prevaccine.

The total number of children who tested positive fell by almost 60 percent.

“That’s fairly dramatic,” said Jerry Bridgham, M.D., chief medical officer of Wolfson Children’s Hospital, who was not involved in the study. “It’s a wonderful thing for the patients and for practicing pediatricians — it gives them validation that the vaccine they have been administering to children for the past couple of years is very effective.”

The nature of the rotavirus season changed after vaccine introduction as well. In the prevaccine years and 2007, the season started in January and ended in May or June, but in 2008, the season started eight months later than usual.

Decreased infections and a delayed season are in keeping with CDC studies of national data. But in northeast Florida, the researchers noticed an additional feature that has not been reported previously. The season lasted longer than usual — prolonged by about three months in 2008. There was no defined season in 2009.

The researchers are continuing to study what factors might be influencing the apparent changes.

“It’s going to take several seasons to figure out what is really happening, and before we can say what the season is, if any,” Rathore said.

Eliminating rotavirus would greatly reduce health-care costs associated with hospitalizations, outpatient treatment and routine testing for the disease and help improve productivity of parents and caregivers who otherwise have to take time off from work to tend to children who can’t go to daycare centers because of the contagious disease.

“It’s a very cost-effective practice to spend a little bit of money on prevention in the form of a vaccine to save an awful lot of money downstream,” Bridgham said. “It affects not only the children, but also their families and communities.”